import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.FutureTask;

public class CallableDemo {


    public static void main(String[] args) throws ExecutionException, InterruptedException {
        Callable<Integer> callable=new  Callable<Integer>() {
            @Override
            public Integer call() throws Exception {
                int sum=0;
                for(int i=0;i<1000;i++) {
                    sum+=i;
                }
                return sum;
            }
        };
        //Thread不能传入callable作为参数,借助FutureTask作为中间值
        FutureTask<Integer>  futureTask=new FutureTask<>(callable);
        Thread t=new Thread(futureTask);
        t.start();
        //后续通过futureTask拿到callable返回值
        System.out.println(futureTask.get());
    }

    private static int result;
    public static void main1(String[] args) throws InterruptedException {
        Thread t1=new Thread(()-> {
            int sum=0;
            for(int i=0;i<1000;i++) {
                sum+=i;
            }
            result=sum;
        });
        t1.start();
        t1.join();
        System.out.println("result="+result);
    }
}
